2.0 Analysis 2.1 Flight Preparation and Take-off The pilot and the three passengers were observed to enter the aircraft directly upon their arrival at the terminal building; the engines were started immediately and a delay of several minutes followed before the aircraft began to taxi. This delay is normal and can be accounted for by the requirement to complete cockpit pre-flight checks and by requirements to bring the engine oil to its operating temperature range prior to take-off. The aircraft navigational lighting systems and the runway lights were seen to illuminate when the aircraft began to taxi. As the activation of ARCAL runway lights is radio-controlled, it can be concluded that the aircraft's electrical power generation and radio transmitter systems were functional prior to take-off. The aircraft was observed to become airborne in approximately 2,000 feet (two-thirds of the runway length). Analysis of take-off distance charts in the aircraft flight manual indicates that, under the existing conditions, the aircraft's ground run should have been approximately 1,700 feet. This theoretical take-off distance is consistent with the witness' accounts and leads to a conclusion that the take-off was likely normal with respect to the documented capability of the aircraft. 2.2 Shallow Climb Profile 2.2.1 Initial Climb The aircraft was observed to enter a very shallow climb immediately following its take-off. Although the witnesses had no aviation experience, they were resolute in their assertion that this departure profile was shallower than others that they had observed. The essential element of these observations is that the aircraft departed on a shallow flight profile and remained low from lift-off until impact with the trees. It did not appear to climb normally and then subsequently descend. Two possibilities which may explain this deviation from the recommended night departure profile are described below. 2.2.2 Possibility of Undetected Malfunction It is possible that the aircraft was subjected to some undetected malfunction or abnormality immediately after take-off, and that this malfunction either restricted the aircraft's climb performance, or otherwise distracted the pilot during this critical phase of the flight. This hypothesis is not supported by either the witnesses' description of the flight profile, or by data from the post-accident wreckage analysis. If the pilot had used the recommended company procedure for night departures from remote aerodromes, he would have established a performance climb to an altitude of 500 feet agl. The climb angle for a performance climb at 107 KIAS is approximately ten degrees, and is more than double that of a cruise climb profile. Under these circumstances, the witnesses should have perceived a steeper-than-normal departure angle; however, the observed climb angle was shallower than normal. If a mechanical malfunction had occurred, some evidence of the failure should have been identified in the wreckage. Examination of both engines found no pre-existing discrepancies that would have contributed to a loss of engine power. The left engine oil sump was scuffed by contact with the camshaft gear teeth. This scuffing occurred after the engine was free of the nacelle and is indicative of high rotational energy. Two of the three left propeller blades exhibited bending and twisting normally associated with high engine power; impact markings on the hub indicated that the propeller was in the normal governing range. This evidence indicates that the left engine was producing power at impact. The precise level of power could not be determined but would likely have been in the high power range. Because there is no other contrary evidence, it has been concluded that the positioning of the left magneto switches and throttle was likely due to impact forces. It is normal for aircraft switches and controls to change position during a crash sequence. The right propeller was found in the mid-feathering range at impact; however, light counterweight signature markings, corresponding to a lower blade angle, were found on the propeller hub. The initial tree strikes made by the right propeller were very clean, suggesting a lower pitch angle and high rotational energy. It is believed that the counterweight signature markings were made as a result of this initial tree contact. This evidence of a lower blade angle and high rotational energy indicates that the right engine was likely producing power upon initial tree contact. However, the extent of this power is unknown. The fact that pine needles were found imbedded around the propeller governor suggests that some damage to the propeller governor likely occurred during tree contact. With the propeller governor disabled at this point, the propeller blades would have begun to feather automatically. However, this feathering action would not have been completed before ground impact. The propeller was captured, therefore, in the mid-feathering range. The continuity of all aircraft controls was checked following the accident and no discrepancies were apparent. Elevator, rudder, and aileron trim settings were all determined to be in the normal take-off range for the weight of the aircraft. In summary, the post-accident investigation could find no evidence of any pre-impact, mechanical faults in the engine, propeller, or flight control systems. The aircraft's flight profile does not support the hypothesis that an unidentified malfunction had occurred. Evidence indicates that the aircraft was in a controlled flight attitude (wings-level, at a slight climb angle, and with normal trim settings) at the time of its initial contact with the trees. Additionally, there was only slight lateral deviation of the aircraft's flight path from the extended centre line of the runway. All of the above factors support a conclusion that the engines were producing power and that the aircraft was under positive control at the time of the crash; this conclusion tends to discount a hypothesis that the pilot was responding to an unusual control or propulsion emergency. There was no evidence of any malfunction prior to impact that would have affected the aircraft's initial climb performance. 2.2.3 Possibility of the Pilot Establishing the Shallow Climb Profile During training, it was noted that this pilot would deviate from the recommended night departure profile and allow the aircraft to maintain a shallow climb angle immediately after take-off. The pilot would allow the aircraft to accelerate to its cruise climb speed (115 - 130 KIAS) before commencing a climb to the planned en route altitude. The evidence is consistent with the conclusion that the pilot deviated from the recommended night departure profile and established the shallow climb profile observed during the accident flight. Information derived by test flying a Cessna 310R following the accident indicates that, under flight conditions similar to those of the accident flight, a Cessna 310R will cover a distance of approximately 6,400 feet horizontally from the commencement of its take-off roll to the point where it has accelerated to 130 KIAS (maximum cruise climb speed). The trees that were struck at Sandy Bay were 5,400 feet beyond the initial take-off point and were 40 feet above the runway elevation. If the pilot had established a climb profile similar to the one he had been observed to use in the past, the aircraft could have struck the trees before it had accelerated to its cruise climb speed of 115 to 130 knots. 2.3 Ambient Light Conditions 2.3.1 Ground and Sky Illumination A night departure from a remote northern aerodrome can be a task requiring extra caution. Even in VFR weather conditions, this type of departure requires the pilot to place increased reliance on vision and on basic instrument flying skills. The transition from outside visual references that are used during the take-off run to instrument references used during the initial climb also demands extra vigilance. At night, a reduction of external visual references caused by inadequate ground and sky illumination, coupled with the requirement to use cockpit lighting to illuminate the instrument panel, will increase the difficulty of the departure procedure. Such a lack of external visual reference could have adversely affected the pilot's ability to maintain required visual reference with the ground during the initial climb, or to see and avoid obstacles. 2.3.2 Forward Illumination of Flight Path by Landing Lights Forward illumination of the flight path would be provided by both the nosewheel-mounted taxi light and the two wing-mounted landing lights. As the landing gear was found in the retracted position, the nosewheel-mounted taxi light would not have provided any illumination at the time of impact. It could not be determined whether or not the wing-mounted landing lights were on during the take-off. However, the fact that they were in the stowed position at impact indicates that the wing-mounted landing lights would not have provided forward illumination prior to impact. The absence of forward illumination of the flight path from the aircraft's landing lights during or after the take-off would have prevented the pilot from being alerted to the presence of obstacles and taking action to avoid collision. 2.4 Medical Issues The pilot had been issued a commercial licence under flexibility for vision and his eyesight was being monitored by medical professionals on a semi-annual basis. Corrective lenses had been prescribed for this pilot and he was required to wear a set of bifocal glasses while flying. It was important that he wear these corrective lenses on a continuing basis in order to maintain his eyes' adaptation to the large degree of correction in the lenses. Failure to properly use his glasses would have deprived him of the corrective qualities of his lenses, which could have affected his instrument visual scanning ability, created difficulty in transitioning from visual to instrument flight, and adversely affected his level of instrument flying ability. There is no evidence that he made improper use of his glasses. Although the pilot's current duties required that he fly at night and under IFR conditions, the practical flight test that the AMRB originally required him to take was conducted during daylight hours in VFR conditions. Flight at night or under IFR conditions would have placed greater demands on the pilot's vision, and a practical flight test conducted under these conditions would have been more difficult for the pilot to pass. Although the medical category had been issued with flexibility for vision, and the AMRB had required a practical flight test and semi-annual eye examinations, the Transport Canada licensing authority did not apply any restrictions to this pilot's licence, as referred to in the Transport Canada Licensing Manual, Volume 3, section 2.0, other than requiring the use of glasses while flying. 2.5 Pathology/Toxicology Levels of non-prescription antihistamines, which were termed therapeutic by the examining laboratory, were evident in the pilot's urine; this indicates that the medication was taken long enough before the occurrence to allow for metabolism and clearance of the drug, thus avoiding any sedative effect. Moreover, although drowsiness may be a side effect of such drugs, since therapeutic levels of antihistamines were not detected in the pilot's blood, an active effect at the time of the accident would not be anticipated. Therefore, it is unlikely that the presence of these antihistamines had affected the pilot's performance. 2.6 Behavioral Factors - Illusions and Disorientation The forward acceleration of the Cessna 310 aircraft is sufficient to produce a powerful illusion of increasing pitch. Under extremely dark night conditions, with restricted outside visual references, a somatogravic illusion could cause the pilot to erroneously conclude that the aircraft was rotating to an increasingly high pitch angle. This illusion would be intensified if the pilot were denied accurate visual information because of a weak instrument scan, degraded eyesight, or poor ambient external lighting. 2.7 Management and Regulatory Issues The pilot was licensed and certified for the flight in accordance with governing regulations and statutes. However, a number of weaknesses in the pilot's basic instrument flying performance had been identified and documented by Transport Canada and the company training personnel. Senior management within the company were also aware of the pilot's weak instrument flying performance. The underlying cause of the weak performance had not been identified, nor documented in either the company or the Transport Canada files. The monitoring of a pilot's performance is a joint responsibility that is shared by the airline company and by Transport Canada. However, despite ongoing difficulties, and despite early identification of weaknesses in instrument flying skills, no effective control mechanism was applied by either agency to monitor the pilot's performance trends, or to ensure that the pilot was not placed in a situation that was beyond his ability to cope successfully. Transport Canada did not forward information concerning the pilot's weak instrument flying performance to the RAMO, nor was there a requirement for them to do so. The performance degradation could have been indicative of inadequate vision and the provision of such information to the RAMO might have resulted in a re-evaluation of the pilot's medical status. The chief pilot recommended that the pilot be given the opportunity to gain additional operational experience in the multi-engine IFR environment by flying as first officer on the company's scheduled Cessna 404. Such an arrangement could also have provided an opportunity to better assess the pilot's performance during instrument flight. The chief pilot was effectively prevented from exercising this responsibility when the company president decided to allow additional training on the C-310 aircraft, and directed that the additional training be conducted in Prince Albert, under the guidance and control of the general manager. Despite the pilot's subsequent failure of the Transport Canada instrument flight test and the PPC and the further additional training required for him to finally pass the flight test and the PPC on the Cessna 310, there were no particular restrictions subsequently applied to the operational employment of the pilot by the company's management. 3.0 Conclusions 3.1 Findings